Have just had new pvc windows installed and they have sealed the outside perimeter of the windows with white silicon. I am now trying to masonary paint over this but the paint will not adhere to the slippery surface. any sugestions? thanks

I make no wonder there are no replies to this one..... everything separates on this sealant. Just keep applying coats around it and it should catch and bond with itself eventually. Applying any covering bonding agents will just peel off in the bad weather anyway!